.header {
    background-color: white;
    .header-top {
        height: 40px;
        border-bottom: 1px solid #1DA57A;
        text-align: right;
        line-height: 40px;
        .username {
            margin: 0 8px 0;
        }
    }

    .header-bottom {
        display: flex;
        height: 40px;
        .header-bottom-left {
            position: relative;
            width: 30%;
            text-align: center;
            font-size: 20px;
            line-height: 40px;
            // "&"表示的是同一个元素的伪元素
            &::after {
                position: absolute;
                left: 50%;
                transform: translateX(-50%);
                top: 40px;
                content:'';
                border-top: 20px solid white;
                border-right: 20px solid transparent;
                border-bottom: 20px solid transparent;
                border-left: 20px solid transparent;
            }
        }
        .header-bottom-right {
            width: 70%;
            text-align: right;
            line-height: 40px;
            img {
                width: 40px;
                height: 40px;
            }
            span {
                margin: 0 10px 0;
            }
        }
    }
}